Various wireless protocols have been used to remotely control one device with another, including infrared, Bluetooth, Wi-Fi. Typically, infrared remote controls are not able to penetrate through walls or other opaque objects. Other wireless controls operating at certain other radio frequencies are able to penetrate opaque devices, e.g., some remotes permit users to control audio/video receivers even if the receiver is stored contained in a cabinet with an opaque, closed door.
Some remote controls require the user to pair the remote with the device to be controlled. For example, if a user wants to use a wireless controller to control a new game console, the console may ignore the content of signals emitted by the controller until the user presses a particular button on the console and a particular button on the controller, thus indicating the user wishes to use that controller with the console.